Preserving the Starry Night in the Glare of Light Pollution

DEATH VALLEY NATIONAL PARK, Calif. — High atop Dante’s View, overlooking sheets of salt flats and ribbons of sand dunes, Dan Duriscoe shined a laser beam at the North Star and steadied his digital camera at the starry heavens.

“You can see the Luxor vertical beam,” said Mr. Duriscoe, pointing to a shot on his camera-connected laptop showing the searchlight of the Luxor, the pyramid-shaped hotel on the Vegas Strip. “That’s the brightest thing out there.”

Acclaimed for its ink-black skies, Death Valley, the hottest place in North America, ranks among the nation’s unspoiled star-gazing spots. But the vista has grown blurry.

The neon glow from Las Vegas and its fast-growing bedroom communities is stealing stars from the park’s eastern fringe. New research reveals that light pollution from Las Vegas increased 61 percent from 2001 to 2007, making it appear brighter than the planet Venus on clear nights as seen from Dante’s View.

Mr. Duriscoe, a scientist with the National Park Service, is part of a team of night owls whose job is to gaze at the sky and monitor light pollution in parks. “What is alarming to me is, what’s going to happen three or four generations from now if this growth of outdoor lights continues?” he asked.

Amid such concerns, Death Valley, the largest national park in the Lower 48, has set out to be the first official dark-sky national park. Studies have shown exposure to artificial lights can interrupt animals’ biological clocks and disrupt ecosystems. Migratory birds have been known to be confused by blinding lights on skyscrapers and fly into them. Last year, the cancer arm of the World Health Organization listed the graveyard shift, where workers toil under artificial lights, as a probable carcinogen.

The International Dark-Sky Association, an Arizona-based nonprofit whose slogan is “Carpe Noctem,” has noticed an increased awareness of light pollution, but acknowledged limits.

“I don’t think you can get Paris to turn off the Eiffel Tower or persuade Times Square to turn off all of its lights,” said Pete Strasser, the group’s managing director.

The same could probably be said for Las Vegas. “It’s the selling point of Las Vegas,” said Barbara Ginoulias, director of comprehensive planning for Clark County, Nev., which includes Las Vegas. Still, she added, “We’re certainly cognizant of light pollution, and we try to address it in the best way.”

Ms. Ginoulias’s department oversees parts of Clark County, which are required to shield outdoor lights or cast the light downward. Next month, the County Commission will consider an ordinance to set standards on digital billboards on Interstate 15, along the Strip. On the city’s main drag, Las Vegas Boulevard, Ms. Ginoulias said, signs are reviewed case by case.

With no control over Las Vegas, Death Valley rangers are looking to fix the problem at home as they aim to be a dark-sky national park. To achieve that, the park must shield or change two-thirds of its outdoor fixtures. Death Valley has about 700 lights in its 3.3 million acres.

So far, Gold Tier Natural Bridges National Monument in Utah and Cherry Springs State Park in Pennsylvania are the only two parks certified by the International Dark-Sky Association as dark-sky enclaves. This fall, the group gave tentative approval to the Geauga Park District’s Observatory Park east of Cleveland.

A version of this article appears in print on , on page A22 of the New York edition with the headline: Preserving the Starry Night in the Glare of Light Pollution. Order Reprints|Today's Paper|Subscribe